The specific aims of the Pathology Core: 1. To provide a blinded reference diagnosis and consensus review of all clinical and animal model material as well as the quantitative cytology and histology specimens. 2. To archive, store and enter in a database all histopathologic specimens and biopsy material (e.g., embedded blocks, frozen tissue, tissue sections) related to Projects by Lam, You, Anderson, and Wattenberg. 3. To prepare pathology slides for routine and special histopathologic examinations (molecular markers and morphometry) required for the conduct of the clinical and animal model projects. 4. To identify areas of pathologic interest for examination by quantitative techniques. 5. To coordinate and correlate diagnostic and special histopathologic data. 6. To stain and evaluate a set of molecular markers on selected sectioned material. 7. To consult with other scientists on the project to ensure the biologic relevance of this work.